mirror of https://github.com/octoleo/restic.git
125 lines
2.4 KiB
Go
125 lines
2.4 KiB
Go
package restic
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"encoding/hex"
|
|
"fmt"
|
|
"io"
|
|
|
|
"github.com/minio/sha256-simd"
|
|
)
|
|
|
|
// Hash returns the ID for data.
|
|
func Hash(data []byte) ID {
|
|
return sha256.Sum256(data)
|
|
}
|
|
|
|
// idSize contains the size of an ID, in bytes.
|
|
const idSize = sha256.Size
|
|
|
|
// ID references content within a repository.
|
|
type ID [idSize]byte
|
|
|
|
// ParseID converts the given string to an ID.
|
|
func ParseID(s string) (ID, error) {
|
|
if len(s) != hex.EncodedLen(idSize) {
|
|
return ID{}, fmt.Errorf("invalid length for ID: %q", s)
|
|
}
|
|
|
|
b, err := hex.DecodeString(s)
|
|
if err != nil {
|
|
return ID{}, fmt.Errorf("invalid ID: %s", err)
|
|
}
|
|
|
|
id := ID{}
|
|
copy(id[:], b)
|
|
|
|
return id, nil
|
|
}
|
|
|
|
func (id ID) String() string {
|
|
return hex.EncodeToString(id[:])
|
|
}
|
|
|
|
// NewRandomID returns a randomly generated ID. When reading from rand fails,
|
|
// the function panics.
|
|
func NewRandomID() ID {
|
|
id := ID{}
|
|
_, err := io.ReadFull(rand.Reader, id[:])
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return id
|
|
}
|
|
|
|
const shortStr = 4
|
|
|
|
// Str returns the shortened string version of id.
|
|
func (id *ID) Str() string {
|
|
if id == nil {
|
|
return "[nil]"
|
|
}
|
|
|
|
if id.IsNull() {
|
|
return "[null]"
|
|
}
|
|
|
|
return hex.EncodeToString(id[:shortStr])
|
|
}
|
|
|
|
// IsNull returns true iff id only consists of null bytes.
|
|
func (id ID) IsNull() bool {
|
|
var nullID ID
|
|
|
|
return id == nullID
|
|
}
|
|
|
|
// Equal compares an ID to another other.
|
|
func (id ID) Equal(other ID) bool {
|
|
return id == other
|
|
}
|
|
|
|
// MarshalJSON returns the JSON encoding of id.
|
|
func (id ID) MarshalJSON() ([]byte, error) {
|
|
buf := make([]byte, 2+hex.EncodedLen(len(id)))
|
|
|
|
buf[0] = '"'
|
|
hex.Encode(buf[1:], id[:])
|
|
buf[len(buf)-1] = '"'
|
|
|
|
return buf, nil
|
|
}
|
|
|
|
// UnmarshalJSON parses the JSON-encoded data and stores the result in id.
|
|
func (id *ID) UnmarshalJSON(b []byte) error {
|
|
// check string length
|
|
if len(b) != len(`""`)+hex.EncodedLen(idSize) {
|
|
return fmt.Errorf("invalid length for ID: %q", b)
|
|
}
|
|
|
|
if b[0] != '"' {
|
|
return fmt.Errorf("invalid start of string: %q", b[0])
|
|
}
|
|
|
|
// Strip JSON string delimiters. The json.Unmarshaler contract says we get
|
|
// a valid JSON value, so we don't need to check that b[len(b)-1] == '"'.
|
|
b = b[1 : len(b)-1]
|
|
|
|
_, err := hex.Decode(id[:], b)
|
|
if err != nil {
|
|
return fmt.Errorf("invalid ID: %s", err)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// IDFromHash returns the ID for the hash.
|
|
func IDFromHash(hash []byte) (id ID) {
|
|
if len(hash) != idSize {
|
|
panic("invalid hash type, not enough/too many bytes")
|
|
}
|
|
|
|
copy(id[:], hash)
|
|
return id
|
|
}
|